[Fuchsia] Add tolerance thresholds for four cc/tree tests

These tests show some pixels difference on Fuchsia on ARM64.
The differences are similar to those on Windows on ARM64.

Bug: 1048249
Change-Id: I2a1742b0412ffe7d1f8613ba49604515d949dec5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2036284Reviewed-by: weiliangc <weiliangc@chromium.org>
Commit-Queue: Chong Gu <chonggu@google.com>
Cr-Commit-Position: refs/heads/master@{#738619}

cc/trees/layer_tree_host_pixeltest_filters.cc

@@ -860,17 +860,22 @@ TEST_P(LayerTreeHostFiltersPixelTest, RotatedFilter) {
 
   background->AddChild(child);
 
-#if defined(OS_WIN)
+#if defined(OS_WIN) || defined(OS_FUCHSIA)
 #if defined (ARCH_CPU_ARM64)
-  // Windows ARM64 has some pixels difference: crbug.com/1029728
+  // Windows ARM64 and Fuchsia has some pixels difference
+  // crbug.com/1029728, crbug.com/1048249
   float percentage_pixels_large_error = 0.391112f;
   float average_error_allowed_in_bad_pixels = 1.1f;
   int large_error_allowed = 3;
-#else
+#elif defined(OS_WIN)
   // Windows has 1 pixel off by 1: crbug.com/259915
   float percentage_pixels_large_error = 0.00111112f;  // 1px / (300*300)
   float average_error_allowed_in_bad_pixels = 1.f;
   int large_error_allowed = 1;
+#else
+  float percentage_pixels_large_error = 0.0f;  // 1px / (300*300)
+  float average_error_allowed_in_bad_pixels = 0.0f;
+  int large_error_allowed = 0;
 #endif
   float percentage_pixels_small_error = 0.0f;
   int small_error_allowed = 0;
@@ -914,7 +919,7 @@ TEST_P(LayerTreeHostFiltersPixelTest, RotatedDropShadowFilter) {
   background->AddChild(child);
 
 #if defined(OS_WIN) || defined(ARCH_CPU_ARM64)
-#if defined(OS_WIN) && defined(ARCH_CPU_ARM64)
+#if (defined(OS_WIN) && defined(ARCH_CPU_ARM64)) || defined(OS_FUCHSIA)
   // Windows ARM64 has some pixels difference: crbug.com/1029729
   float percentage_pixels_large_error = 0.89f;
   float average_error_allowed_in_bad_pixels = 5.f;

cc/trees/layer_tree_host_pixeltest_masks.cc

@@ -764,10 +764,10 @@ class LayerTreeHostMaskAsBlendingPixelTest
       small_error_allowed = 1;
     } else {
 #if defined(ARCH_CPU_ARM64)
-#if defined(OS_WIN)
-      // Windows ARM64 has some pixels difference
+#if defined(OS_WIN) || defined(OS_FUCHSIA)
+      // Windows and Fuchsia ARM64 has some pixels difference
       // Affected tests: RotatedClippedCircle, RotatedClippedCircleUnderflow
-      // crbug.com/1030244
+      // crbug.com/1030244, crbug.com/1048249
       percentage_pixels_error = 6.1f;
       average_error_allowed_in_bad_pixels = 5.f;
       large_error_allowed = 20;